Aging usually weakens calcium-containing tissues such as bone and tooth. Bone tissues undergo without cease the formation and absorption of bone which are kept in an adequate balance in younger living bodies. Such a balance may be lost by a variety of causes such as unbalanced hormone secretion which is caused by extreme diet and aging, resulting in an excessive bone absorption. If such a state prolongs, then calcium-containing tissues such as bone and tooth loose calcium, one of their important elements, and this may accelerate the incidence of bone disorders such as osteoporosis, bone break and backache, as well as of tooth disorders such as dental caries and periodontosis.
Calcium in living bodies is present in a calcium phosphate solid such as hydroxyapatite: It plays an important role in the formation of bone and tooth and strengthening their tissues, as well as functioning as a source for calcium ion which is indispensable for living bodies. It is said that Japanese people may be lack for calcium intake, and this has triggered the commercialization of various health foods directed to supplement calcium. The way of supplementing calcium however should be carefully chosen because calcium intake may be ineffective due to its less assimilativity, as well as because an excessive intake may cause hypercalcemia. Because of these, it has been recommended that in order to deposit calcium in tissues, calcium is intaken as nutrient, then other minerals such as magnesium is intaken to accelerate the assimilativity and metabolism of calcium. This however has been proved insufficient for effectiveness. With the same purpose, lipid soluble vitamins and hormones such as vitamin D, calcitonin, estrogen, protein anabolic hormone and bisphosphonate are administered together with these minerals. The method however has not been proved satisfiable: It may be more effective than sole intake of calcium but lead to complicated administration schedule for lipid-soluble vitamins and hormones when such a vitamin or hormone is used because their excessive administration is causative of undesirable side effects.
The present invention is to provide a non-toxic agent for strengthening calcium-containing tissues with safeness, as well as to provide its uses including foods, cosmetics and pharmaceuticals to which such agent is incorporated.